$ git clone -n https://src.fedoraproject.org/rpms/rust-tracing-core.git /var/lib/mock/f42-build-side-1-3586835-46926/root/chroot_tmpdir/scmroot/rust-tracing-core
Cloning into '/var/lib/mock/f42-build-side-1-3586835-46926/root/chroot_tmpdir/scmroot/rust-tracing-core'...
$ git fetch origin 6cbe988ffe8cfd817b07968ae062fc20acf72044:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-tracing-core
 * [new ref]         6cbe988ffe8cfd817b07968ae062fc20acf72044 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6cbe988 Update to version 0.1.34; Fixes RHBZ#2370618